A scientist randomly divided a group of 100 lab rats into two groups of 50. One group was fed regular rat chow while the other was fed the same amount of rat chow with added DDT. Both groups were housed in the same room with the same environmental conditions. At the end of the experiment, rats were weighed and the mean difference calculated. Refer to the accompanying narrative. What variable or variables were manipulated by the scientist?

Dichlorodiphenyltrichloroethane (DDT) may be defined as the colorless chemical used as an insecticide in the field. But the DDT is accumulated in the environment and cause pollution.

The experiment given in the question explains the effect of DDT. Here, the manipulated variable or the treatment variable because its value is changed in the experiment. The rat is treated with the DDT and its effect is noticed in the experiment. The experiment depends on the value of DDT and acts as the manipulated variable.

Thus, the answer is DDT.

Arclight Arclight · Answer 2 · 2020-02-07T07:01:51+01:00

Answer:

Addition of DDT in food

Explanation:

The variable that was manipulated during the study was the food given to the two groups of rat.

All other factors such as the number of rats in each group, amount of food, room condition and environmental condition were same for both groups.

With addition of DDT in food (rat chow) of one of the group, scientist has manipulated the study process for one of the group.

This was done with the purpose of understanding the effect of DDT on the weights on the rats of one group by comparing it with the rats of another control group (constant factors)